Internal combustion engine with liquid-cooled cylinder liners



Nov. 12, 1968 o. HERSCHMANN INTERNAL COMBUSTION ENGINE WITHLIQUID-COOLED CYLINDER LINERS Filed Jan. 5, 1966 R 0 MN N EA C S R E H OU 0 United States Patent 3,410,256 INTERNAL COMBUSTION ENGINE WITHLIQUID- COOLED CYLINDER LINERS Otto Herschmann, Fellbach, Wurttemberg,Germany, assignor to Daimler-Benz, Aktiengesellschaft, Stuttgart-Unterturkheim, Germany Filed Jan. 3, 1966, Ser. No. 518,285; Claimspriority, application Germany, .ian. 12, 1965, 1) 46,232 9 Claims. (Cl.123-4134) ABSTRACT OF THE DISCLOSURE An internal combustion enginehaving liquid-cooled cylinder liners, whose ends facing the cylinderhead are each provided with a radial collar for the securing at thecrankcase, and in which the cylinder head is secured at the crankcase bymeans of cylinder head bolts. The radial collar engages the topmost flatsurface of the crankcase. A rigid spacer plate is provided between thecrankcase topmost fiat surface and the cylinder head for absorbingsubstantially all of the forces exerted by the cylinder head bolts. Aneasily compressible sealing ring is provided between the radial collarand the cylinder head, which will not unduly stress the radial collar.The liquid cooling bores extend through the spacer plate and into theannular space between the crankcase and the liners closely adjacent tothe respective radial collars.

Background of the invention With internal combustion engines of theaforementioned type, it is known to provide the seat at the crankcasefor the collar of the cylinder liner recessed with respect to theseparating joint between the crankcase and the cylinder head.Disadvantageous notch loads and stresses are created thereby at the seatof the crankcase by the cylinder head securing means in that seals whichproject over the separating surface at the crankcase and which aresupported at the liner collar, are compressed for increasing the sealingelfect. As a result of the notch stresses, cracks form at the crankcasewithin the area of the seat for the cylinder liners so that thecrankcase is destroyed or damaged.

It is known in connection with internal combustion engines for purposesof sealing the separating joint between the crankcase and the cylinderhead that at least one of the two parts is provided in proximity of itsouter edges, outside of the area of the cylinder head bolts and thesealing rings, with non-yielding spacer bars on which rests the cylinderhead, comparable to a doubly supported beam, in such a manner that upontightening of the cylinder head bolts a considerable bending of thecylinder head in the direction toward the sealing rings compressedthereby takes place. This known support and securing of the cylinderhead, constructed in the manner of a bending bearer, could provide nosuggestion for the present invention.

Summary of the invention The aim underlying the present inventionessentially consists in eliminating the notch stresses of the crankcasewhich occur in the manner described above in an internal combustionengine of the aforementioned type and to relieve the cylinder head fromthe disadvantageous static bending loads and stresses of the cylinderhead securing means. For this purpose, the radial collar of eachcylinder liner is placed in accordance with the present invention uponthe crankcase and non-yielding spacer pieces are arranged within thearea of the cylinder head bolts be- 3,410,256 Patented Nov. 12, 1968tween the crankcase and the cylinder head. In one embodiment of thepresent invention, a spacer plate is provided between the crankcase andthe cylinder head which is provided with apertures for the passages ofthe combustion spaces, cooling water spaces, oil lines and the likebetween the crankcase and the cylinder block.

Accordingly, it is an object of the present invention to provide aninternal combustion engine having liquidcooled cylinder liners whicheliminates by extremely simple means, the aforementioned shortcomingsand drawbacks encountered in the prior art constructions.

Another object of the present invention resides in a liquid-cooledinternal combustion engine having cylinder liners cooled by a liquid inwhich notch stresses are avoided at the seat of the crankcasenotwithstanding a completely satisfactory and tight securing of thecylinder head to the cylinder block.

A further object of the present invention resides in an internalcombustion engine having liquid-cooled cylinder liners which assuregreater life expectancy by the elimination of the danger of cracking ofthe crankcase.

Still another object of the present invention resides in a liquid-cooledinternal combustion engine which not only achieves all of theaforementioned aims and objects by simple and operationally reliablemeans but which additionally improves the cooling of the cylinder linersin an effective manner.

Brief description 01'' the drawing These and further objects, features,and advantages of the present invention will become more obvious fromthe following description when taken in connection with the accompanyingdrawing which shows, for purposes of illustration only, one embodimentin accordance with the present invention and wherein:

FIGURE 1 is a partial cross-sectional view through the crankcase of aninternal combustion engine in accordance with the present invention; and

FIGURE 2 is a partial cross-sectional View through a different portionof the engine of FIGURE 1 showing the cylinder head bolts.

Detailed description 0 the drawing Referring now to FIGURE 1 of thedrawing, reference numeral 10 designates therein a crankcase of aninternal combustion engine of conventional constructon and not shown indetail herein. A liquid-cooled cylinder liner 11 is inserted into thecrankcase 10. The cylinder liner 11 is provided at the end facing thecylinder head 12 with a radial collar 13. The collar 13 is placed uponthe separating surface 14 of the crankcase 10. A spacer plate 15 isarranged between the crankcase 10 and the cylinder head 12. The spacerplate 15 is provided with apertures 16 for the combustion spaces 17 andwith further apertures 18 for the cooling liquid passage.

The cylinder head 12 is secured at the crankcase 10 in a conventionalmanner by means of cylinder head bolts (not shown) extending through thespacer plate 15. A seal 19 is arranged between the collar 13 of thecylinder liner 11 and the cylinder head 12 by means of which thecombustion space 17 is sealed in a gas-tight manner against the cylinderhead 12 and the cylinder liner 11.

The cross section of the crankcase 10 is devoid of any notches withinthe support or abutment area of the radial collar 13 so that the dangerof crack formation within this area of the crankcase is avoided in afar-reaching manner.

With tightened cylinder head bolts, the cylinder head 12 is exposedstatically essentially only to those loads and stresses which resultfrom the compressing of the cylinder head seals 19.

The apertures 18 of the spacer plate 15 for the passage of the coolingliquid are in communication with axial bores 20 in the crankcase 10. Thecooling liquid flows through the annular space 21 between the crankcaseand the cylinder liner 11; the annular space 21 is in communication byway of radial connecting bores 22 with the axial bores 20 of thecrankcase.

Since the radial collar 13 of the cylinder liner is not mounted in thecrankcase recessed with respect to the separating surface 14 but insteadis placed or mounted upon this surface, the radial connecting bores 22for the passage of the cooling liquid can be moved more closely to theend of the cylinder liner 11 near the cylinder head and therewith thecooling of the cylinder liner can be improved in an effective manner.

Generally, corresponding numerals are used in FIG- URE 2 forcorresponding elements shown in FIGURE 1. The spacer plate is providedwith passage bores 23 for the cylinder head bolts 24. The bolts 24 arethreaded into the crankcase with the threaded studs 26 thereof and aresupported with a collar 25 upon the separating surface 14. A gasket 27is concentrically positioned about each bolt 24 between the respectivecollar 25 and the cylinder head 12. The cylinder head 12 is providedwith bores 28 through which the cylinder head bolts 24 extend. Thetensioning of the bolts is accomplished by means of the nuts 29threadably engaging the bolts 24.

While I have shown and described only one embodiment in accordance withthe present invention, it is understood that the same is not limitedthereto but is susceptible to numerous changes and modifications asknown to a person skilled in the art, and I therefore do not wish to belimited to the details shown and described herein, but intend to coverall such changes and modifications as are encompassed by the scope ofthe appended claims.

I claim:

1. An internal combustion engine comprising: a cylinder head; acrankcase having a flat surface facing said cylinder head; a pluralityof pistons within said crankcase; cylinder liners surrounding saidpistons, respectively, and spaced from said crankcase to form coolingliquid conducting spaces; cylinder bolt means securing said cylinderhead to said crankcase; each of said cylinder liners being provided withradial collar means having one surface axially facing, parallel to anddirectly opposite from said crankcase surface; and essentiallynon-yielding spacer means arranged Within the area of the cylinder boltmeans engaging said crankcase surface and said cylinder head fordirectly and rigidly absorbing substantially all of the clamping forceof said bolt means.

2. The internal combustion engine according to claim 1, wherein saidspacer means is constituted by a spacer plate being provided withaperture means for the cylinder bolt means and with passage means forthe cooling liquid and the combustion spaces opposite the pistons.

3. The internal combustion engine according to claim 2, wherein saidcrankcase includes approximately axial bore portions and connecting boreportions extending at an angle to said axial bore portions andterminating in the annular spaces formed between the cylinder liners andthe crankcase, said spacer means being provided with aperture means inalignment with said axial bore portions, and said connecting bore meansbeing located relatively close to the collar means.

4. The internal combustion engine according to claim 1, wherein saidcrankcase includes approximately axial bore portions and connecting boreportions extending at an angle to said axial bore portions andterminating in the annular spaces formed between the cylinder liners andthe crankcase, said spacer means being provided with aperture means inalignment with said axial bore portions, and said connecting bore meansbeing located relatively close to the collar means.

5. The internal combustion engine according to claim 1, wherein saidsurface of the crankcase directly engages said collar means, and is theexposed relatively plane topmost surface of the crankcase means.

6. The internal combustion engine according to claim 4, wherein saidsurface of the crankcase directly engages said collar means, and is theexposed relatively plane topmost surface of the crankcase means.

7. The internal combustion engine according to claim 3, wherein saidsurface of the crankcase directly engages said collar means, and is theexposed relatively plane topmost surface of the crankcase means.

8. The internal combustion engine according to claim 2, wherein saidradial collar means are disposed within respective ones of said passagemeans for the combustion spaces opposite the pistons; and includingreadily compressible annular sealing rings between said radial collarmeans and said cylinder head; said cylinder head and liners havinginterengaging annular tongue and groove means radially inwardly ofrespective ones of said sealing rings.

9. The internal combustion engine according to claim 3, wherein saidconnecting bore means is axially spaced at its inner end from saidcrankcase surface a distance substantially corresponding to thethickness of said spacer means.

References Cited UNITED STATES PATENTS 1,220,335 3/1917 Heinze 92171 X2,378,045 6/1945 Sorensen et al. 12341.72 X 2,679,241 5/1954 Dickson123193 3,209,659 10/1965 Colwell 12341.84 X 1,306,843 6/1919 Wolgamott12341.84 2,710,602 6/1955 Maybach 123-41.82 X 3,139,009 6/1964 Harting123193 X FOREIGN PATENTS 391,386 4/1933 Great Britain. 455,334 10/ 1936Great Britain.

AL LAWRENCE SMITH, Primary Examiner.

